The constructor of sun.net.httpserver.Request has the following do/while loop:

do {
            startLine = readLine();
            if (startLine == null) {
                return;
            }
            /* skip blank lines */
        } while (startLine == null ? false : startLine.equals (""));

There's a if condition within the loop which makes the while (startLine == null) check redundant. The loop condition can be simplified to make it much more simpler to read.

(A contributor has a PR open for this change https://github.com/openjdk/jdk/pull/9571 )